INDEX 



521 



Optic 



ganglia, 16, 369 

 ganglion, 95, 166 

 groove, 11, 12, 13 

 lobe, of cephalopods, 164, 166 

 inner granular layer, 166 

 outer granular layer, 166 

 nerve, 52, 361, 370 



degeneration of in mole, 239 

 of lateral eyes of scorpion, 132 

 nerve fibres, preretinal, 15, 54, 149, 370 

 relation of to retina, 48, 54 

 of scorpions and spiders, 373 

 pit, 21, 48, 161, 370, 371 

 pulvinar of, 415 

 radiations, 438 

 rudiment, 11 

 thalamus, 416 

 vesicle(s), accessory, 203 

 of Murex, 49 

 primary, 15 

 Orbital cavities, position of in Ostracoder- 



mata, 191 

 Ordovician period, 350 

 Organs, light percipient, 178 

 Ornithorhynchus, 46, 323 

 Orthoceras, 151 

 Osteichthyes, 337 

 Osteodentine, 474 

 Osterolepis macrolepidotus, 182, 336 

 Osteoplastic flap, 441, 443, 447 

 Osteostraci, 344 

 Ostracodermi, 191, 135, 327, 344, 359, 378, 



380, 465, 473 

 Otocyst. See Statocyst 



of Phallusia, 5, 175 

 Ovary, increase in size in pinealectomized 



bird, 423 

 Oviducts, increase in length of in pineal- 

 ectomized bird, 423 

 Owl, Epiphysis of, 297 

 Oxidase, 60 

 Oyster, 147 



Paddle-fish, 73 



imperforate parietal canal of, 209 

 Paired 



organs, fusion of, 47, 328 



pineal pits, 329, 330 

 Palceaspis, 378 

 Palcemon 



serratus, 143 



sqailla, retinulae of compound eye, 52 

 Palceohatteria, 267 

 PalEeospondyloidea, 344 

 Paheostraca, 136, 349 

 Palaeozoic sea-scorpions, 473 

 Palinurus, median and lateral eyes of 



phyllosoma larva, no 

 Pandalns ammlicornis, 143, 144 

 Papilledema, 439, 449, 452 

 Parallel development, 354 

 Paramcecia, effect of pineal extract on, 426 

 Paraphysal arch, 180, 204, 224 



Paraphysis, 180, 183, 193, 224, 226, 240, 

 244, 251, 285, 286, 307, 314, 369, 468 



absence of, 184 

 Parapineal organ, 68, 71, 184, 185, 253 

 absence of in Mordacia, 198 

 of Petromyzon, 187 

 Parasitic, Arachnida, degeneration of sense- 

 organs in, 131 

 Parenchyma cells, 323, 398 

 branched, 317, 318 

 containing granules, 317 

 degeneration of, 469 

 Parietal 



bones, fusion of, 268, 301 

 canal of Titanosuchus, 339 

 centre, 278 



cornea, 69, 74, 181, 274 

 evagination, origin of, 242-244 

 eye, 273, 363, 479 



absence of in Ophidia, 284 



absence of in birds, 288 



absence of in mammals, 299 



of arthropods (Patten), 378 



of lamprey, 379 



phylogenetic origin of, 245 



present only in embryo, 282 



tubercle, 471 



of tunicates, 378 



variability in differentiation, 284 

 fleck, 181 

 foramen, 181, 200, 273, 282 



absence of, 268, 269, 288 



absence of in Dipnoi, 336 



absence of in Molge cristata, 227 



absence of in living snakes, 284 



bilateral, 202 



contents of, 270 



closing membrane of, 280 



in Dicynodon, 300 



disappearance of, 268 



dome-shaped, 248 



in embryonic skull, 269 



in frontal bone, 182 



heart-shaped, 200 



of Labyrinthodonts, 235 



obliteration of, 300 



in Pythonomorpha, 284 



shape of, 270 



size of, 270 

 impression, 181, 182 

 nerve(s), 283, 278 



absence in adult Iguana, 279 



absence of in primary diverticulum, 



245 

 bilateral, 279 

 degeneration of, 278 

 ganglion of, 278 

 independent formation of, 243, 



279 

 termination in right habenular 



ganglion, 278 

 organ(s), 4, 181, 184 



absence of in Crocodilia, 240 

 accessory, 244, 245, 248 

 of Agamidce, 273 

 bilateral origin of, 187, 245 



